Wages and salaries (and, perhaps, prices) would not go down. Your argument and the parent of it, is falling for the lump of labor fallacy. By adding supply of labor, the demand for labor goes up as well. It is actually well-agreed on by economists, but I see many smart people, on the left and right, get it wrong.
I implore you both to read and listen about it (google/"lump of labor").
I implore you both to read and listen about it (google/"lump of labor").